<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>css制作三角形</title>
    <style>
        .demo1{
            width: 0;
            height: 0;
            border-width: 20px;
            border-style: solid;
            border-color: transparent transparent #ff8d73  transparent;
        }
        .demo2{
            width: 0;
            height: 0;
            border-width: 20px;
            border-style: solid;
            border-color: #ff8d73 transparent transparent #ff8d73;
        }
    </style>
</head>
<body>
    <div class="demo1"></div>
    <br>
    <div class="demo2"></div>
</body>
</html>